package com.leetcode;

import com.leetcode.common.TreeNode;

import java.util.LinkedList;
import java.util.Queue;

/**
 * 104. 二叉树的最大深度
 * bfs广度优先搜索
 *
 * @author fy
 * @date 2022-04-17 15:45
 */
public class Solution104_1 {

    public int maxDepth(TreeNode root) {
        if (root == null) {
            return 0;
        }
        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(root);
        int res = 0;
        while (!queue.isEmpty()) {
            int size = queue.size();
            for (int i = 0; i < size; i++) {
                TreeNode node = queue.poll();
                if (node.left != null) {
                    queue.offer(node.left);
                }
                if (node.right != null) {
                    queue.offer(node.right);
                }
            }
            res++;
        }
        return res;
    }

}
